Embodiments of the inventive concept relate generally to semiconductor memory devices. More particularly, embodiments of the inventive concept relate to nonvolatile memory devices and methods of operating the nonvolatile memory devices.
Semiconductor memory devices can be roughly divided into two categories according to whether they retain stored data when disconnected from power. These categories include volatile memory devices, which lose stored data when disconnected from power, and nonvolatile memory devices, which retain stored data when disconnected from power.
Examples of volatile memory devices include static random-access memory (SRAM) devices, dynamic random-access memory (DRAM) devices, and synchronous dynamic random-access memory (SDRAM) devices. Examples of nonvolatile memory devices include read-only memory (ROM) devices, programmable read-only memory (PROM) devices, electrically programmable read-only memory (EPROM) devices, electrically erasable and programmable read-only memory (EEPROM) devices, flash memory devices, phase-change random-access memory (PRAM) devices, magnetic random-access memory (MRAM) devices, resistive random-access memory (RRAM) devices, and ferroelectric random-access memory (FRAM) devices. Flash memory devices can be further divided into two categories including NOR-type flash memory devices and NAND-type flash memory devices.
A flash memory device typically comprises a memory cell array divided into a plurality of memory blocks. Each memory block is further divided into a plurality of pages. Data is programmed or read in the memory cell array in page units, and erased from the memory cell array in block units.